Device for locating the position of the control rack of a pump and for locking the latter in disassembling position

Abstract

A variable displacement pump, the delivery of which is controlled through the medium of a toothed rack meshing with a pinion through which the piston of the pump is adapted to slide axially, said piston being adapted to rotate jointly with said pinion and to move in translation jointly with pump actuation means, and the toothed rack meshing with an auxiliary shaft pinion the angular position of which is located by an indicating needle, thus ensuring a measurement of the delivery of said pump.

What is claimed is: 
     
       1. Variable displacement pump, for use as a fuel injection pump for an internal combustion engine or the like of the type provided with a constant delivery-stroke piston, the angular position of which inside a casing for the pump determines a particular amount of fluid delivered in each cycle, comprising a toothed rack having a toothed portion, a pinion cooperating with said toothed portion through which said piston is adapted to slide axially, said piston being movable in translation jointly with pump actuating means and to rotate jointly with said pinion for varying said angular position and therefore said particular amount; said pump also including means for displaying said particular amount, comprising an auxiliary shaft pinion adapted to rotate about its own longitudinal center-line disposed in meshing relationship with said rack and supporting an indicating needle supported by said last-named pinion, a graduated sector over which said needle is movable; said pump being also of the type wherein at a given angular position of said piston the latter may be removed from the pump casing and whereby one end of said auxiliary shaft pinion is accessible, said end comprising driving square means for enabling said rack to be displaced manually through the medium of said auxiliary shaft pinion. 
     
     
       2. Pump according to claim 1, wherein said needle is directly mounted on said auxiliary shaft pinion through the medium of a needle-carrying member and wherein said needle-carrying member is mounted on said driving square. 
     
     
       3. Pump according to claim 1, including means for locking said auxiliary shaft pinion in a predetermined angular position corresonding to said given angular position of the said pinion. 
     
     
       4. Pump according to claim 2, including means for locking said auxiliary shaft pinion in a predetermined angular position corresponding to a given angular position of the said pinion. 
     
     
       5. Pump according to claim 4, wherein said locking means include said needle-carrying member and comprise in addition a removable or retractable stop, abutment, pin or the like co-operating with said needle-carrying member and so arranged as to keep said needle-carrying device beyond a normal sector of movement with respect to the aforesaid graduated sector, in said predetermined angular position. 
     
     
       6. Pump according to claim 1, wherein the aforesaid auxiliary shaft pinion co-operates with an auxiliary toothed portion of said rack distinct from the aforesaid toothed portion actuating the first-mentioned pinion, said toothed portions being substantially symmetrical with respect to a longitudinal axial plane of said rack and approximately opposed to one another.